An effective, green, scalable, and sustainable approach for removing chemical contaminants from drinking water and groundwater.
Poly- and perfluoroalkyl substances (PFAS) are persistent manmade chemicals that have been widely used since the 1950s. Across the United States, hundreds of sites have been contaminated by these anthropogenic compounds, and more than 6 million Americans are consuming water containing them. Sorption is the most commonly used technique for removing PFAS from drinking water and groundwater; yet, the technique has a number of drawbacks. It is energy consuming and the process is generally conducted in engineered vessels that are not inexpensive to build and maintain. Further, when multiple PFAS are present in the influent, the technique’s selective removal allows some PFAS to appear in the effluent. In addition, the spent media must be shipped off-site for disposal through landfilling or commercial incineration.
Researchers at the University at Albany have devised a method for removing PFAS from the environment that combines phytoremediation, the use of plant biomass to absorb chemicals, with hydrothermal liquefaction, a process that uses heat and pressure to degrade chemicals while also producing biofuels that when burned give off no net carbon emissions.
In their studies, the team examined uptake of the chemicals GenX, ADONA and F-53B by broadleaf cattails. They found that these chemicals were readily absorbed by the cattails and that hydrothermal liquefaction completely degraded GenX and ADONA. F-53B, however, was resistant to the hydrothermal liquefaction treatment; yet, by increasing the temperature and adding calcium hydroxide to the treatment, the team was able to achieve 100% degradation of F-53B.
The team concluded that its method of employing plant uptake followed by hydrothermal liquefaction “is an effective, green, scalable and sustainable approach for removing PFAS from contaminated environments.”
• Cheaper, cleaner and more energy-efficient than traditional techniques.
• Addresses a key challenge of phytoremediation, which is how to handle contaminants-laden plant biomass.
• May produce biocrude that can be used in other applications.
• Eliminates contaminants from drinking water and groundwater.
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